Apparatus for applying mold wash to molds



Aug. 16, 1955 c. E. YATES 2,715,385

APPARATUS FOR APPLYING MOLD WASH TO MOLDS Filed Sept. 25, 1951 ATTO R NEYS United States Patent APPARATUS FOR APPLYING MOLD WASH TO MOLDSCharles E. Yates, New York, N. Y., assignor to International Smellingand Refining Company, a corporation of Montana Application September 25,1951, Serial No. 248,179

7 Claims. (Cl. 118-12) This invention relates to apparatus for applyingmold wash to the interior of molds, and for like purposes. It isparticularly directed to apparatus having a system in which mold washcontinuously circulates in a closed path, mold wash being withdrawn froma mold wash reservoir and reintroduced into the reservoir by acirculation pump, until a spray nozzle connected with the system isintroduced into the interior of a mold and a circulation control valveis thereby automatically caused to close and thus to divert mold washout of its circulation path to the nozzle which sprays it uniformlythroughout the mold.

Metallic molds in which molten metal is cast are customarily coated withan oily or aqueous suspension of graphite or bone black or finelydivided alumina or like material. Such a suspension is called mold wash.The coating of mold wash reduces sticking of the castings to the molds,and helps to give each casting a smooth surface free from pits and otherdefects. It has been common practice heretofore, especially with respectto small-diameter vertical billet molds, to apply the mold wash manuallyby swabbing the mold interior with a mop dipped in mold wash.

The apparatus of the present invention greatly reduces the laborinvolved in applying mold wash and insures uniform coating of the moldinterior. It also reduces the quantity of mold wash consumed in coatinga given number of molds in comparison with the amount used in manualswabbing of the same number of molds.

The new apparatus comprises a tank containing mold wash, and an inletpipe and an outlet pipe each communicating with said tank, together witha circulation pump connected between said pipes, whereby mold washnormally is circulated continuously from the tank through the outletpipe and thence through the inlet pipe back again to the tank. Acirculation control valve is connected in the inlet pipe. Spring meansurging the valve to its closed position are provided, but the valvenormally is held open, through a valve operating lever, so thatcirculation of the mold wash from the tank and back again to the tankmay take place.

A feed pipe is connected with the inlet pipe between the circulationpump and the valve, and a spray nozzle is connected by a flexibleconnection to said feed pipe. Means are provided so that when the nozzleis introduced into a mold, to spray its interior with mold wash, thecirculation control valve is caused to close, with the result that themold wash is diverted from the circulation path and is delivered throughthe nozzle. In a particularly advantageous embodiment of the apparatus,the nozzle is suspended for movement vertically into or out of the mold,and is normally held out of the mold by a counterweight. Thecounterweight in turn actuates the valve operating lever to hold thevalve open. When, however, the nozzle is lowered into the mold, thecounterweight releases the valve operating lever, and the spring meansthereupon causes it to close, so that mold Wash is delivered to thenozzle and is sprayed into the mold in ice the manner described. Whenthe nozzle is removed from the mold by raising it to the upper limit ofits path of travel, the counterweight again actuates the valve operatinglever, opening the valve and restoring the flow of mold wash to itsnormal path of circulation from the tank and back again into the tank.

It is advantageous to incorporate a check valve in the feed pipeconnected with the inlet pipe, such check valve being arranged so as toprevent flow of mold wash through the feed pipe toward the tank, andcreating an appreciable resistance to the flow of mold wash therethroughfrom the tank. Thereby, inadvertent leakage of mold wash from the nozzlewhen it is out of the mold is rendered much less likely to occur, and atthe same time the feed pipe itself and the connections between it andthe spray nozzle may be kept full of mold wash at all times.

The foregoing and other features of the invention are described belowwith reference to the accompanying drawings, in which Fig. 1 is aschematic showing of an advantageous embodiment of the invention; and

Fig. 2 is an elevation, partially in longitudinal section, of anadvantageous form of nozzle.

In Fig. 1 the apparatus is shown in its normal condition ready for use.The apparatus comprises a mold wash supply tank 5 whose walls aresurrounded by steam coils 6. These steam coils heat the mold wash whileit circulates through the tank and increase its fluidity. The supplytank has an outlet pipe '7, leading from its bottom and communicatingwith the interior of the tank through a filter screen 8 which surroundsthe open end of the outlet pipe 7 and serves to prevent circulation ofany coarse solid impurities which may find their way into the tank. Ascraper 9 can be slid up and down on the outer surface of the filterscreen 8 to scrape off impurities which may block the holes in thescreen and impede the flow of mold wash.

An inlet pipe 10 opens into the upper portion of the tank. The outletpipe 7 and the inlet pipe 10 are each connected to a circulation pump12, thus together forming a mold wash circulation system in which thecirculation pump 12 withdraws mold wash through the out let pipe 7 andpumps it back into the tank through the inlet pipe 10. A sparecirculation pump 13 is a standby pump to supply mold wash through asimilar circulation pipeline 14 to a spare spray unit (not shown in thedrawing) identical with the main spray unit described below. The spareunit can be employed in case of breakdown of the main unit. A four-waycock 15 is placed at the juncture of circulation pipes 10 and 14 and isnormally set so as to cut off the spare pipe unit 14 and to allow freeflow through the pipeline 10.

A circulation control valve 16 is connected in the inlet pipe 10.Normally the valve 16 is open and permits the circulation pump 12 tocontinuously withdraw mold wash from the tank 5 through the outlet pipe7 and return it thereto through the inlet pipe 10 and the valve 16. Thevalve 16 should be of a quick-opening, quickclosing type, such as a gatevalve. The valve is operated by a lever 19 attached by a slot and pinconnection to its stern. Normally the valve 16 is held open by a weight20 which rests upon the hooked lower end of a lever operating rod 21.The rod 21 can slide freely up and down vertically in guide bearings 22,and is attached to the valve lever 19 at its upper end by a slot and pinconnection. The lever 19 pivots about a fulcrum support 23. A spring 24is attached to the lever 19 and continually urges the valve 16 to itsclosed position. When the weight 20 is raised, it releases the lever 19and the spring 24 quickly closes the valve 16.

A mold wash feed pipe 25 connects with the inlet pipe 10 at a pointbetween the circulation pump 12 3 and the quick-closing valve 16. Acheck valve 26 is placed in the feed pipe 25 to prevent back-flowtowards the supply tank 5. Thereby, once the feed pipe and equipmentconnected to it have been 'filled with mold wash, they will be keptfilled at all times. Also, the check valve 26 provides flow resistancein the feed pipeline 25 so that when the quick-closing valve 16 is open,mold Wash will simply circulate back to the supply tank 5 through thevalve 16 and will not tend to escape through the feed pipe 25. The feedpipe connects with a pair of pneumatic spray nozzles 27 through valves28 and flexible mold wash hoses 29 (two spray nozzles are shown by wayof example to illustrate the arrangement used for applying mold washsimultaneously to two molds positioned side-by-side). 30 indicates thepressure in the feed pipe 25.

A suspension cable 31 is attached at one end to a frame member 32supporting the spray nozzles 27 and passes over a pair of pulleys 33.The cable 31 has its opposite end attached to the counterweight 20 whichrests upon the lever operating rod 21. When the nozzles 27, whichare'suspended from the cable 31 and can thus be lowered and raised in avertical path'into and out of the interior of molds, are at the upperlimit of their vertical path, the counterweight 20 rests upon the leverhook 21 and holds the valve operating lever 19 in an the flow of moldwash into the feed pipe 25 and through the mold wash hoses 29 to thespraying nozzles 27.

The apparatus as above described is of course particularly adapted forspraying mold wash into molds M which are mounted on a casting wheel Wor other device by which they are advanced into position under the spraynozzles, and by which they are subsequently withdrawn from suchposition. The particular form of the molds, and of the device for movingthem into and out of position under the spray nozzles, is conventionaland forms no part of this invention.

Compressed dry air is supplied to the pneumatic spray ing nozzles 27through rubber air hoses 34 from an air line 35 connected to an airdrier system 36. Valves 37 are placed just before the air hoses 34 toregulate the air flow therein. An air gauge 38 indicates the airpressure in the compressed air line 35, and a regulator valve 39 isconnected-in the air line .35 to regulate the air pressure. Compressedair is supplied to the air drier system 36 through an air supply pipe 40and enters a storage tank 41 which is provided with a trap '42 to removecondensed water and other liquids. The air then passes through a pipe 43to driers 44 of conventional design. One or both of these air driers 44may 'be placed in operation to remove moisture from the compressed airby properly setting valves 45. The compressed air then passes throughthe air line 35 and hoses 34 to the pneumatic spray nozzles 27.

Fig. 2 shows in detail one of the pair of pneumatic spray nozzleassemblies 27 advantageously employed in the spraying apparatusdescribed above. The nozzle structure comprises a central pipe 46 whichcommunicates with the mold wash supply hoses 29 and extends down throughthe interior of an air supply cylinder 47 in concentrically spacedrelationship with the walls of such cylinder. The air hose 34communicates with the interior of the air supply cylinder 47 through aside intake 48. The cylinder 47 is made airtight at the top by means ofa cap plate 49 which is bolted to a packing gland bushing 50 so as tocompress a packing washer 51 tightly against the walls of the centralpipe 46. The lower end of the bushing 50 is internally threaded andscrews securely on to the corresponding threaded upper -end of thecylinder 47.

A pressure gauge The lower end of the central pipe 46 is threaded into anipple 52 which is itself screw-threaded to the lower end of thecylinder 47. Air channels 53 are formed longitudinally through thenipple 52 in. concentric relation about an axial mold wash channel 54. Adeflector 55 having a central mold wash channel 56 passing axiallythrough it is threaded into the lower end of nipple 52 so that itschannel 56 communicates with the axial mold wash channel of the nipple52 and through it with the pipe 46. A nozzle 57 screw-threaded to thelower end of the nipple defines a mixing cavity 58 at the lower end ofthe deflector 55, to which cavity mold wash is delivered through thechannel 56 and to which air is delivered through an annular air passage59 formed between the wall of the nozzle and the deflector 55. Airflowing from the intake 48 passes down through the air cylinder 47,through the nipple air channels 53 and then through the annular passage59, from which it is delivered to the mixing chamber 58 in the form of aconverging conical jet. When mold wash is delivered under pressure tothe mixing chamber 58, it is blown by the air jet through the nozzleorifice 58 in the form of a conical spray.

A protective sleeve 60 is fitted over the lower end portion of thenozzle assembly. The protective sleeve is provided with radial spacingfins 61 which Serve to center the nozzle assembly as it is lowered intothe interior of a mold, and thus help to produce a uniform coating ofmold wash on the interior of a mold.

In the operation of the above-described spraying apparatus, thecirculation pump 12 is started while the counterweight 20 is restingupon. the lever operating rod 21, whereby mold wash is continuouslywithdrawn from the supply tank 5 and circulated through the inlet pipe14) and the open valve 16 back into the supply tank. The apparatus thusis in condition ready for a spraying operation. When it is desired tospray the interior of a pair of molds M, the operator lowers the spraynozzles 27 into such molds, whereby the-counterweight 20 is raised fromthe lever operating rod 21, releasing the valve lever 19 and causing thevalve 16 to close under the urging of the spring 24. Thereupon mold washis diverted through the feed pipe 25 and into the pneumatic nozzles. Ithas been found advantageous to maintain a mold wash pressure of between20 and 40 pounds per square inch in the inlet pipe 10 and the feed pipe25 when the valve 16 is closed. Regulation of mold wash pressure may beachieved by having a variable speed drive on circulation pump 12. a

Air is supplied to the pneumatic nozzles through the air line 35 and innormal operations flows constantly out of the nozzles, whether theapparatus is in spraying operation or not. An air pressure of about 6 to8 pounds per square inch in the air line 35 has been found adequate.

Since the spray of mold wash begins as soon as the spray nozzle beginsto move down through the mold, and stops as soon as the nozzle is raisedout of the mold, the apparatus of this invention has been found todeposit an ample coating of mold wash on copper billet molds, and yet toefiect a substantial saving of mold wash in comparison with the amountrequired using other application procedures. A minimum of physicalelfort is re.- quired, with the result that a single operator canperform all the spraying of molds that required the efforts of severalmen when using the heretofore conventional manual methods for applyingmold Wash to billet molds.

I claim:

1. Apparatus for applying mold Wash to the interior of a mold comprisinga tank containing mold wash, an inlet pipe and an outlet pipeeachcommunicating with said tank, a circulation pump connected betweensaid inlet and said outlet pipes, whereby mold wash is circulated fromthe tankthrough the outlet pipe and through the inlet pipe back to thetank, anormally open circulation control valve connected in said inletpipe, a valve operating lever, spring means urging said valve closed, aspray nozzle communicating with said inlet pipe through a flexible hoseconnection and movable in a vertical path into and out of said mold, anda counterweight normally holding said nozzle in an elevated position outof said mold and holding said valve operating lever in position to holdsaid valve open in opposition to the urging of said spring means, saidcounterweight releasing said lever when the nozzle is lowered into themold, thereby enabling said valve to be closed for so long as saidnozzle is lowered into the mold.

2. Apparatus for applying mold wash to the interior of a mold comprisingtank containing mold wash, an inlet pipe and an outlet pipe eachcommunicating with said tank, a circulation pump connected between saidinlet and said outlet pipes and serving to circulate mold wash from thetank through the outlet pipe and through the inlet pipe back to thetank, a normally open circulation control valve connected in said inletpipe, a springbiased valve operating lever through which said valve isurged closed, a spray nozzle connected through a flexible hoseconnection to said inlet pipe, said nozzle being suspended for movementin a vertical path into and out of said mold, and a counterweightnormally holding said nozzle in its elevated position out of said moldand actuating the operating lever of said valve so as to hold said valveopen against the urging of said spring bias, saidcounterweight'releasing said lever whenever said nozzle is lowered intothe mold, thereby allowing said valve to close and remain closed untilsaid nozzle is raised again to the upper limit of its path of travel.

3. Apparatus for applying mold wasn to the interior said tank, acirculation pump connected between said inlet and said outlet pipes, acirculation control valve connected in said inlet pipe, lever meansnormally holding said valve open, whereby said pump normallycontinuously withdraws mold wash from said tank through said outlet pipeand introduces it back into said tank through said inlet pipe and valve,a mold wash feed pipe communicating with said inlet pipe between saidvalve and said pump, a pneumatic spray nozzle communicating with saidfeed pipe through a flexible hose connection, said nozzle being movablein a vertical path into and out of said mold, and counterweight meansnormally holding said nozzle out of the mold and normally actuating saidlever means to hold said valve open, said counterweight means releasingsaid lever to cause said valve to close and thus to direct mold wash tothe said nozzle Whenever said nozzle is moved into said mold.

4. Apparatus for applying mold wash to the interior of a mold comprisinga tank containing mold wash, an inlet pipe and an outlet pipe eachcommunicating with said tank, a circulation pump connected between saidinlet and said outlet pipes, said pump normally circulating mold washcontinuously from the tank through said outlet pipe and through saidinlet pipe back into said tank, a normally open circulation controlvalve connected in said inlet pipe, a mold wash feed pipe communicatingwith said inlet pipe between said control valve and said pump, apneumatic spray nozzle, a flexible hose connection between said feedpipe and said nozzle, said nozzle being movable in a vertical path intoand out of said mold, spring means urging said control valve closed, andmeans actuated by movement of said nozzle out of said mold to overcomethe force of said spring means and open said control valve.

5. Apparatus for applying mold wash to the interior of a mold comprisinga tank containing mold wash, an inlet pipe and an outlet pipe eachcommunicating with said tank, a circulation pump connected between saidinlet and said outlet pipes, said pump normally circulating mold washcontinuously from the tank through said outlet pipe and through saidinlet pipe back into said tank, a normally open circulation controlvalve connected in said inlet pipe, a mold wash feed pipe communicatingwith said inlet pipe between said control valve and said pump, a checkvalve connected in said feed pipe, said check valve preventing fiowthrough said feed pipe toward said tank and creating appreciableresistance to the flow of mold Wash therethrough from sand tank, apneumatic spray nozzle, a flexible hose connection between said feedpipe and said nozzle, said nozzle being movable in a vertical path intoand out of said mold, spring means urging said control valve closed, andmeans actuated by movement of said nozzle out of said mold to overcomethe force of said spring means and open said control valve.

6. Apparatus for applying mold wash to the interior of a mold comprisinga tank containing mold Wash, an inlet pipe and an outlet pipe eachcommunicating with said tank, a circulation pump connected between saidinlet and said outlet pipes, said pump normally circulating mold washcontinuously from the tank through said outlet pipe and through saidinlet pipe back into said tank, a circulation control valve connected insaid inlet pipe, a mold Wash feed pipe communicating with said inletpipe between said control valve and said pump, a pneumatic spray nozzle,21 flexible hose connection between said feed pipe and said nozzle, saidnozzle being movable in a vertical path into and out of said mold, levermeans for opening said control valve, spring means operably connected tosaid lever means for closing said control valve, and means actuated bymovement of said nozzle out of said mold operating said lever means toovercome the force of said spring means and thereby open said controlvalve.

7. Apparatus for applying mold wash to the interior of a mold comprisinga tank containing mold Wash, an inlet pipe and an outlet pipe eachcommunicating with said tank, a circulation pump connected between saidinlet and said outlet pipes, said pump normally circulating mold washcontinuously from the tank through said outlet pipe and through saidinlet pipe back into said tank, a circulation control valve connected insaid inlet pipe, a mold wash feed pipe communicating with said inletpipe between said control valve and said pump, a check valve connectedin said feed pipe, said check valve preventing flow through said feedpipe toward said tank and creating appreciable resistance to the flow ofmold wash therethrough from said tank, a pneumatic spray nozzle, aflexible hose connection between said feed pipe and said nozzle, saidnozzle being movable in a vertical path into and out of said mold, levermeans for opening said control valve, spring means operably connected tosaid lever means for closing said control valve, and means actuated bymovement of said nozzle out of said mold operating said lever means toovercome the force of said spring means and thereby open said controlvalve.

References Cited in the file of this patent UNITED STATES PATENTS

